Millimeter-wave detect or reflect array

ABSTRACT

A device for detecting and selectively reflecting an incident microwave signal or millimeter-wave signal is disclosed. The device includes a plurality of antennae disposed in an array; and a diode disposed at each input of each antenna, each diode having an input adapted to selectively receive a reverse bias signal, or a zero bias signal, or a forward bias signal. The device also includes a switching device connected to each input, and configured to selectively apply the forward bias signal, or the reverse bias signal or the zero bias signal to each of the diodes. In forward bias, each of the plurality of antennae reflects the incident microwave signal or millimeter wave signal; and in zero bias or reverse bias each of the plurality of antennae detects the incident microwave signal or millimeter wave signal.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part under 37 C.F.R. § 1.53(b) ofcommonly owned U.S. patent application Ser. No. 16/547,681 to Lee, etal. entitled “Millimeter-Wave Detect or Reflect Array” filed on Aug. 22,2019 The present application claims priority under 35 U.S.C. § 120 toU.S. patent application Ser. No. 16/547,681, the disclosure of which ishereby incorporated by reference in its entirety. The presentapplication also claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application No. 62/751,796, filed on Oct. 29, 2018, andnaming Gregory S. Lee, et al. inventors. The entire disclosure of U.S.Provisional Application No. 62/751,796 is hereby specificallyincorporated by reference in its entirety.

BACKGROUND

Automotive radars are currently deployed in autos for assistance inparking and collision avoidance. Additionally, driverless cars arecurrently being developed, and these types of cars may incorporate suchautomotive radars. While light detections and ranging (LIDAR) may play arole in this scenario, it is generally conceded that radar has the clearadvantage in fog and offers the unique ability to determine relativevelocity due to the Doppler effect. Each car may be equipped with asmany as a dozen automotive radar modules around the perimeter of thecar. Thus, auto manufacturers are preparing for when they will soon beinstalling millions of radar units inside car bodies (in the bumpers,doors, etc.).

Auto radars mainly operate near 77 GHz, although there are short rangeradars (SRRs) at 24 GHz and there may be future radars operating at 120GHz. At all these millimeter-wave frequencies, the thickness of theplastic composites used in the car bumpers and doors is comparable to orlarger than the wavelength. Furthermore, this thickness is not verytightly controlled (from an electromagnetic radiation standpoint) andthe surfaces are highly curved. These factors imply that the directionalperformance of a radar module as tested before it is installed in thecar part will change after installation.

Particularly, direction of arrival (DOA) of a target is an importantparameter to estimate, especially for mid-range radars (MRRs) andlong-range radars (LRRs). For long-range radars the desired azimuthalaccuracy is 0.1°. Car manufacturers now mechanically translate cornerreflectors as test targets to test the installed radar accuracy. Thecorner reflector distance must be at least 1 m to avoid deleteriousdiffraction/scattering effects from its edges and outer walls. A shortertest distance would be desirable as this would save space on theautomotive assembly line. There is a tradeoff between positioningaccuracy, needed to establish the rigorous relative angle, and demandsfor speed typical of assembly lines to maintain throughput. Multi-targettesting in an assembly line environment has been discussed, but slingingmultiple corner reflectors around in such an environment becomes evenmore problematic.

All scenarios envision the mid-range radars placed in the bumpercorners, four per vehicle. The plastic curvature is so high in theseareas that the corners act as uncontrolled millimeter-wave lenses. Forthese radar units, even the raw transmit beams may be severelydistorted. Thus, analogous to the “headlight tweaking” that to which theauto industry is accustomed, carmakers envision tweaking the transmitarrays of installed radars to compensate for beam skew. At present, theyhave no method to measure the installed module transmit pattern that issufficiently inexpensive, small, and fast.

Notably, space, time, and cost are of such concern on the vehicleassembly line that a system/method that can test both the radar transmitbeam pattern and its full (transmit/receive roundtrip) angular accuracyis highly desirable. If separate test equipment is needed to test thevarious radar functionalities, one can appreciate that assembly linespace is wasted and testing time and cost increase.

Moreover, the cars discussed above are assumed to be pristine vehiclesthat are just being readied to ship. Upon ownership, accidents or justplain denting will occur so body work will be needed. For example, oneor more radars may be damaged in an accident and need replacing. Even ifall the car's radars survive intact, new bumpers, new paint, etc. willchange their performance. A typical body shop can less afford equipmentcost, time, and space than an assembly line, yet “radar touchup” will berequired. One can appreciate that the needs highlighted in the previousparagraphs become even more acute.

BRIEF DESCRIPTION OF THE DRAWINGS

The example embodiments are best understood from the following detaileddescription when read with the accompanying drawing figures. It isemphasized that the various features are not necessarily drawn to scale.In fact, the dimensions may be arbitrarily increased or decreased forclarity of discussion. Wherever applicable and practical, like referencenumerals refer to like elements.

FIG. 1A illustrates an antenna-diode pair for an antenna-coupled diodeused in a two-dimensional array of antenna-coupled diodes, in accordancewith a representative embodiment.

FIG. 1B illustrates a two-dimensional array of antenna-diode pairs usedin a two-dimensional array of antenna-coupled diodes, in accordance witha representative embodiment.

FIG. 2A illustrates a top view of geometry of an antenna-diode pair witha tapped antenna on a printed circuit board, in accordance with arepresentative embodiment.

FIG. 2B illustrates a front view of geometry of the antenna-diode pairwith the tapped antenna on a printed circuit board of FIG. 2A, inaccordance with a representative embodiment.

FIG. 3A illustrates a front view of a two-dimensional array ofantenna-diode pairs used in a two-dimensional array of antenna coupleddiodes, in accordance with a representative embodiment;

FIG. 3B illustrates a side view of the two-dimensional array ofantenna-diode pairs used in a two-dimensional array of antenna coupleddiodes of FIG. 3B, in accordance with a representative embodiment;

FIG. 4 illustrates a piecewise flat surface on which subarrays of thetwo-dimensional array of FIG. 1B are fabricated, in accordance with arepresentative embodiment.

FIG. 5 illustrates a flow for testing an installed automotivearrangement, in accordance with a representative embodiment.

FIG. 6 illustrates a system for testing an installed automotivearrangement using the flow of FIG. 5 in a first use case, in accordancewith a representative embodiment.

FIG. 7 illustrates a system for testing an installed automotivearrangement using the flow of FIG. 4 in a second use case, in accordancewith a representative embodiment.

FIG. 8 illustrates a general computer system, on which a method ofcontrolling the two-dimensional array of antenna-diode pairs can beimplemented, in accordance with a representative embodiment.

FIG. 9 illustrates an arrangement for determining angle of incidence ofa radar signal in accordance with a representative embodiment.

FIG. 10A illustrates a simplified schematic diagram of a circuit fordetermining an angle of incidence of a radar signal from a device undertest (DUT).

FIG. 10B illustrates a simplified schematic diagram of a circuit fordetermining an angle of incidence of a radar signal from a device undertest (DUT).

FIG. 10C illustrates angle of incidence of incident millimeter wave ormicrowave signals at two neighboring antennae in accordance with arepresentative embodiment.

FIG. 11 illustrates a rectenna device in accordance with anotherrepresentative embodiment.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation andnot limitation, representative embodiments disclosing specific detailsare set forth in order to provide a thorough understanding of anembodiment according to the present teachings. Descriptions of knownsystems, devices, materials, methods of operation and methods ofmanufacture may be omitted so as to avoid obscuring the description ofthe representative embodiments. Nonetheless, systems, devices, materialsand methods that are within the purview of one of ordinary skill in theart are within the scope of the present teachings and may be used inaccordance with the representative embodiments. It is to be understoodthat the terminology used herein is for purposes of describingparticular embodiments only and is not intended to be limiting. Thedefined terms are in addition to the technical and scientific meaningsof the defined terms as commonly understood and accepted in thetechnical field of the present teachings.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements or components, theseelements or components should not be limited by these terms. These termsare only used to distinguish one element or component from anotherelement or component. Thus, a first element or component discussed belowcould be termed a second element or component without departing from theteachings of the present disclosure.

The terminology used herein is for purposes of describing particularembodiments only and is not intended to be limiting. As used in thespecification and appended claims, the singular forms of terms ‘a’, ‘an’and ‘the’ are intended to include both singular and plural forms, unlessthe context clearly dictates otherwise. Additionally, the terms“comprises”, and/or “comprising,” and/or similar terms when used in thisspecification, specify the presence of stated features, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, elements, components, and/or groups thereof. As usedherein, the term “and/or” includes any and all combinations of one ormore of the associated listed items.

Unless otherwise noted, when an element or component is said to be“connected to”, “coupled to”, or “adjacent to” another element orcomponent, it will be understood that the element or component can bedirectly connected or coupled to the other element or component, orintervening elements or components may be present. That is, these andsimilar terms encompass cases where one or more intermediate elements orcomponents may be employed to connect two elements or components.However, when an element or component is said to be “directly connected”to another element or component, this encompasses only cases where thetwo elements or components are connected to each other without anyintermediate or intervening elements or components.

FIG. 1A illustrates an antenna-diode pair for an antenna-coupled diodeused in a two-dimensional array of antenna-coupled diodes, in accordancewith a representative embodiment.

In FIG. 1A, the antenna-diode pair 110 includes an antenna 112 and adiode 120. The diode 120 is coupled to the antenna 112 and is thereforean antenna-coupled diode. As described more fully below, the diode 120may be a Schottky diode and the antenna 112 may be a patch antenna.

FIG. 1B illustrates a two-dimensional array of antenna-diode pairs usedin a two-dimensional array of antenna-coupled diodes, in accordance witha representative embodiment.

In FIG. 1B, an antenna-diode pair array 100 includes antenna-diode pair110A, antenna-diode pair 110B, antenna-diode pair 110C, antenna-diodepair 110D, antenna-diode pair 110E, and antenna-diode pair 110F. Theview in FIG. 1B is the top view of the antenna-diode pair array 100,corresponding to the X (width) dimension and the Y (height) direction.The antenna-diode pair array 100 is shown as a two-dimension array ofantenna-diode pairs in FIG. 1B. The antenna-diode pair array 100 iscoupled to a switching device 130 which is used to individually controlthe antenna-diode pairs 110 of the antenna-diode pair array 100. Theswitching device 130 includes or is coupled to first signal line 131 andsecond signal line 132. The first signal line 131 and the second signalline 132 may carry signals to individually control the antenna-diodepairs 110 of the antenna-diode pair array 100.

Insofar as the antenna-diode pair array 100 includes both antennae anddiodes, the antenna-diode pair array 100 also includes multiple antennaedisposed in an array and multiple diodes disposed in an array. Eachantenna in the antenna-diode pair array 100 includes an input adapted toselectively receive a forward bias signal, or a zero bias signal, orreverse bias signal. Each diode in the antenna-diode pair array 100 isdisposed at an input of a corresponding antenna. The switching device130 is connected to each input and is configured to selectively apply aforward bias or zero bias or reverse bias to each of the diodes. In zerobias or reverse bias, each of the antennae in the antenna-diode pairarray 100 detects (i.e., receives) the incident microwave signal ormillimeter wave signal. In forward bias each of the antennae in theantenna-diode pair array 100 reflects the incident microwave signal ormillimeter wave signal. Stated somewhat differently, each diode in theantenna-diode pair array is configured to receive a bias, and dependingon the bias, and the antenna is made to detect (receive) or reflectdepending on the bias. To receive (i.e., detect) the bias at the diodeof each antenna-diode pair array 100 is either zero-biased orreverse-biased. To reflect each diode of the antenna-diode pair array100 the diode is forward biased.

Notably, throughout this disclosure the signals of a DUT being testedare often referred to as either millimeter wave or microwave signals. Itis emphasized that this is merely illustrative, and the presentteachings are not limited to testing DUTs that emit at thesewavelengths. More generally, the DUTs contemplated for testing accordingto the present teachings can emit signals in the radio frequency (RF)band. As such, the detect or reflect arrays for testing a DUT accordingto the present teachings are contemplated for operation at frequenciesof the RF band.

Although the antenna-diode pair array 100 is shown in FIG. 1B to includesix antenna-diode pairs 110, an antenna-diode pair array 100 may includemany more than six antenna-diode pairs 110. The antenna-diode pairs 110of the antenna-diode pair array 100 may be arranged in rows and columnsand may be controlled individually and/or in the rows and/or columns.That is, the antenna-diode pair array 100 may include a series of rowsand a series of columns. The antenna-diode pairs 110 in each of theseries of rows may be addressable by the switching device 130. Inforward bias, the addressed rows may detect the incident microwavesignal or millimeter wave signal. In forward bias, the addressed rowsreflect the incident microwave signal or millimeter wave signal.Additionally, the antenna-diode pairs 110 in each of the series ofcolumns may be addressable by the switching device 130. In zero orreverse bias, the addressed columns detect the incident microwave signalor millimeter wave signal. In forward bias, the addressed columnsreflect the incident microwave signal or millimeter wave signal.

In FIG. 1B, bias/sense address lines are not shown in the antenna-diodepair array 100. Each of antenna-diode pair 110A, antenna-diode pair110B, antenna-diode pair 110C, antenna-diode pair 110D, antenna-diodepair 110E, and antenna-diode pair 110F can either be left at zero orreverse bias to operate in detect mode, or forward biased to operate inreflect mode. The individual antenna-diode pairs 110 may be spaced aboutone-half wavelength. Alternatively, the individual antenna-diode pairs110 may be spaced from one another by approximately one quarterwavelength. Whether the spacing of the antenna-diode pairs 110 isapproximately one-half wavelength or approximately one-quarterwavelength, the wavelength used as a reference is the wavelength of themicrowave signal or millimeter wave signal. Additionally, when thespacing is one-half wavelength, the device under test (DUT) which emitsthe microwave signal or millimeter wave signal may transmit a singlebeam such as a single main beam.

At sufficient forward bias, each diode 120 is effectively a shortcircuit. In the mode with the sufficient forward bias, the correspondingantenna simply reflects the locally impinging radiation. By forwardbiasing selected elements while leaving the remainder of theantenna-diode pairs 110 of the antenna-diode pair array 100 at zero biasor reverse bias, a local mirror (or mirrors) is created because theantenna-diode pair 110 at zero or reverse bias act like absorbers. Themirror(s) electronically created using the antenna-diode pair array 100acts as the test target.

One can electronically change the position, size, shape, and number ofmirrors extremely quickly and precisely because there are no movingparts. Changing the mirror position is simply a matter of electronicallyaddressing the desired element(s) to put into forward bias. Theeffective mirror size, which may be important as carmakers test radarcross section (RCS), is determined by the number of contiguous elementsin forward bias. If any of the following criteria is satisfied, neighborelements act from an RF standpoint as if they are continuous rather thandiscrete:

1. Spacing is λ/4 or less.

2. Device under test (DUT) transmits a single main beam and spacing isλ/2 or less.

3. Array is at least D²/λ away from the radar and spacing is λ/2 orless.

Here D is the diameter of the larger of the transmit and receive arraysconstituting the radar being tested and λ is the wavelength. Inpractice, both the latter two criteria are met. For example, when D≅28mm for λ=3.92 mm (the wavelength at 76.5 GHz), meaning D2/λ=0.2 m. Thisis well below the present testing distance with corner reflectors of 1 mor more; furthermore, radars today look for multiple targets by usingadvanced signal processing algorithms rather than by transmittingmulti-beam patterns. Hence, λ/2 spacing in the two-dimensional array maysuffice.

It is also beneficial in some instances to test the shape of an objectin a vehicle's path. By the present teachings, shapes can be emulated bychoosing a piecewise linear perimeter for the contiguous set ofantenna-diode 110 pair of the antenna-diode pair array 100 that closelymatches the desired smooth shape. Finally, multi-target testing maybecome necessary; the number of mirrors is simply the number of separatecontiguous forward bias zones in the array.

In FIG. 1B, an antenna-diode pair array 100 includes an array of (patch)antenna-coupled diodes. Each element in the antenna-diode pair array 100is an antenna—diode pair and can be operated in either a detection modeor a reflection mode. Each antenna 112 in the antenna-diode pair array100 may be spaced approximately one-half wavelength apart from eachadjacent antenna in the antenna-diode pair array 100 in each of twolateral dimensions. Each diode 120 may be a zero bias Schottky diode. Atzero bias one can use a zero bias Schottky diode as a video or squarelaw detector. In this mode, each antenna-diode pair 110 functions as awell-known rectenna, which stand for “rectifying antenna.” Theantenna-diode pair 110 outputs a rectified voltage in proportion to thepower locally received by the antenna 112 of the antenna-diode pair 110.Since each antenna-diode pair 110 is in an antenna-diode pair array 100,the two-dimensional addressing of the rectified voltages provides aglobal radiation power image—thus providing a millimeter-wave camera.This “camera” can be used to image the transmit radiation pattern, e.g.,from a radar installed in the corner of a car bumper or other body part.

FIG. 2A illustrates a top view of geometry of a patch antenna-diode pairwith a tapped patch antenna on a printed circuit board, in accordancewith a representative embodiment.

In FIG. 2A, a patch antenna-diode pair 210 includes a patch antenna 212and a diode 220. An input 211 is shown as a circle at or near the centerof the patch antenna 212, and a bias/sense line 213 that ends at theinput 211 is outlined by broken segments. The diode 220 is connectedwith or otherwise coupled to the patch antenna 212 to form the patchantenna-diode pair 210.

While printed circuit board (PCB) technology is becoming very popularfor various microwave applications, in the millimeter-wave band, patchantennas cannot be directly put onto conventional FR-4 material since itis too lossy. However, designs with patch antenna arrays on low-losslaminate material stacked with FR-4 into multilayer boards may beimplemented. Surface mount diodes, commonly used at lower frequencies,are beginning to appear at millimeter-wave frequencies. FIG. 2Billustrates a view that includes a PCB 240 with FR-4 and low-losslaminate layers.

FIG. 2B illustrates a front view of geometry of the antenna-diode pairwith the tapped antenna on a printed circuit board of FIG. 2A, inaccordance with a representative embodiment.

In FIG. 2B, the bias/sense line 213 that ends at the input 211 is shownrising through a printed circuit board to end at the antenna 212. Theprinted circuit board includes, in order, an FR-R material 243, a groundlayer 242, and a low-loss laminate 241.

In FIG. 2A, the view from the top is defined by the X (width) and Y(depth) directions. In FIG. 2B, the view from the front is defined bythe X (width) and Z (height) directions.

In FIGS. 2A and 2B a simple method is shown for single-ended addressingof each patch antenna-diode pair that avoids inductive choking.

A symmetry feature of patch antennas is invoked in FIGS. 2A and 2B.Namely, the center of the antenna 212 (patch antenna) is an RF voltagenull. A tap via delineated as a circle bounded by broken lines in FIG.2A is placed at this central point, so that the diode 220 can be biasedor the rectified voltage of the diode 220 can be sensed withoutdisturbing the RF fields or allowing them to leak onto the bias/senseline 213. In other words, an input of the antenna 212 is disposed at acenter-tap of the antenna 212, and this may be true of each antenna inthe antenna-diode pair array 100. Bringing the tap via through theground layer 242 (RF ground plane) and out the backside of the PCB 240allows isolation of all bias/sense signals from the radiation. Themeasuring in the detecting mode may include measuring only a directcurrent voltage at the center tap, as the magnitude of the directcurrent voltage will be proportional to the magnitude of the microwavesignal or millimeter wave signal from the DUT. All layers of the PCB 240beneath the ground layer 242 (RF ground plane) can be FR-4 since onlylayers starting with and above the ground layer 242 (RF ground plane)are relevant to the millimeter waves.

In reality, the diode 220 placed at the RF feed point of the antenna 212may slightly break the symmetry. This effect can be modelled withsoftware that simulates electromagnetic effects, and the effect can becompensated by a slight offset in the position of the tap via. Inpractice at 77 GHz, this offset winds up being less than a mil in thedirection opposite the diode 220.

FIG. 3A illustrates a front view of a two-dimensional array ofantenna-diode pairs used in a two-dimensional array of antenna coupleddiodes, in accordance with a representative embodiment.

In FIG. 3A, a first antenna-diode pair 310A, a second antenna-diode pair310B, a third antenna-diode pair 310C, and a fourth antenna-diode pair310D form a row of antenna-diode pairs in the antenna-diode pair array100 in the X (width) direction. A first bias/sense line 313A, a secondbias/sense line 313B, a third bias/sense line 313C, and a fourthbias/sense line 313D respectively end in the inputs to the firstantenna-diode pair 310A, a second antenna-diode pair 310B, a thirdantenna-diode pair 310C, and a fourth antenna-diode pair 310D. Aswitching device 330 switches the first bias/sense line 313A, the secondbias/sense line 313B, the third bias/sense line 313C, and the fourthbias/sense line 313D between biasing and sensing either individually oras a row.

The row shown in FIG. 3A is representative of multiple rows in anantenna-diode pair array 100. Additionally, while only fourantenna-diode pairs are shown in FIG. 3A, it will be understood thatrows of the antenna-diode pair array 100 may include more than fourantenna-diode pairs or fewer than four antenna-diode pairs withoutdeparting from the spirit of the teachings of the present disclosure.

FIG. 3B illustrates a side view of the two-dimensional array ofantenna-diode pairs used in a two-dimensional array of antenna coupleddiodes of FIG. 3B, in accordance with a representative embodiment.

In FIG. 3B, a fifth antenna-diode pair 310E, a sixth antenna-diode pair310F, a seventh antenna-diode pair 310G, and an eighth antenna-diodepair 310H form a column of antenna-diode pairs in the antenna-diode pairarray 100 in the Z (depth) direction in the depicted coordinate system.A fifth bias/sense line 313E, a sixth bias/sense line 313F, a seventhbias/sense line 313G, and an eighth bias/sense line 313H respectivelyend in the inputs to the fifth antenna-diode pair 310E, the sixthantenna-diode pair 310F, the seventh antenna-diode pair 310G, and theeighth antenna-diode pair 310H. A switching device 330 switches thefifth bias/sense line 313E, the sixth bias/sense line 313F, the seventhbias/sense line 313G, and the eighth bias/sense line 313H betweenbiasing and sensing either individually or as a column.

The column shown in FIG. 3B is representative of multiple columns in anantenna-diode pair array 100. Additionally, while only fourantenna-diode pairs are shown in FIG. 3B, it will be understood thatcolumns of the antenna-diode pair array 100 may include more than fourantenna-diode pairs or fewer than four antenna-diode pairs withoutdeparting from the spirit of the teachings of the present disclosure.

FIG. 4 illustrates a piecewise flat surface on which subarrays of thetwo-dimensional array of FIG. 1B may be fabricated, in accordance with arepresentative embodiment.

For retroreflection, it may be desirable to fabricate the antenna-diodepair array 100 as a two-dimensional array on a curved surface. Notably,‘perfect’ retroreflection is not necessary. For example, a cornerreflector can be imperfect due to diffraction/scattering effects.Moreover, real targets are not typically perfect retroreflectors.Accordingly, a curved surface of a car body part surface 498 can becoarsely approximated with a piecewise flat surface as shown by thetiles including Tile 1 451, Tile 2 452 up to Tile N 459 as in in FIG. 4.The tiles from Tile 1 451 to Tile N 459 may be flat subarray tilesarranged to inscribe or circumscribe either a sphere or a cylinder,creating a piecewise flat sphere or a piecewise flat cylinder,respectively. In other words, in FIG. 4, multiple arrays of antennae areprovided by the tiles from Tile 1 451 to Tile N 459. Each of themultiple arrays may be considered a sub-array, and each of the multiplearrays of antennae are substantially flat but together form a curvedarray when placed adjacent to each other. Even though the resultantarray is curved, the array may still be considered a two-dimensionalarray in that the elements of the array are still arranged in twodimensions in each sub-array. For near-term vehicle radars, only azimuthaccuracy needs to be tested so the cylindrical (rather than the moreinvolved spherical) version of the piecewise flat surface may suffice.The center of the cylinder/sphere outlined partially by the piecewiseflat surface should be the approximate center of the radar DUT 499.Since car radars are bistatic, meaning the transmit array is offset fromthe receive array, the approximate center is roughly the mean of thegeometric centers.

In FIG. 4, each tile is a two-dimensional subarray. The car body partsurface is arbitrary, and depends on the body part, its fabricationtolerance, and whether it is dented or not, among other considerations.

FIG. 5 illustrates a flow for testing an installed automotivearrangement, in accordance with a representative embodiment.

In the embodiment of FIG. 5, testing of a radar for a car 590 isillustrated. In transmit and detect modes, a computer (not shown) of thecar 590 may communicate with a computer/controller 560 used for testing.The computer of the car 590 communicates a desired test sequence to thecomputer/controller 560 the radar for the car 590, and thecomputer/controller 560 arranges the appropriate test. For example, thecomputer of the car 590 inform the computer/controller 560 that theradar for the car 590 is transmitting a beam at 48° azimuth, and thecomputer/controller 560 then arranges the test.

In detect mode, the transmit function for the radar of the car 590 istested. This is illustrated in FIG. 6. In the transmit function, thecomputer/controller 560 sets all the diode biases to zero so that theantenna-diode pair array 100 acts as a millimeter-wave camera. Thecomputer/controller 560 then “polls” the sense multiplexer 561 to scanthe antenna-diode pair array 100, thereby collecting the sensedmillimeter-wave power across the camera. Image information such as spotcenter, spot shape, etc. is compared with the desired ideal transmitbeam, and if a discrepancy is deemed unacceptable, the antenna-diodepair array 100 can be adjusted to bring the transmitter into conformanceor the software that controls the beam forming can be adjusted tocorrect for the measured offset. The adjusting (physical or software)may be performed by a technician or by the car 590 itself. The adjustingmay be mechanical or electrical, or both, to bring the transmitter intoconformance.

In reflect mode, DUT transmission and reception are both fully tested.This is illustrated in FIG. 7. In the reflect mode, the test systememulates a radar target at varying angles. For example, azimuth accuracytests may be important to an automaker, so the computer/controller 560may instruct the bias demultiplexer 562 to forward bias only the columnin the antenna-diode pair array 100 corresponding to the target azimuthwhile leaving all other columns at zero bias to be nonreflecting. Whenboth azimuth and elevation are targeted, the row and column bias selectmay be implemented through the bias demultiplexer 562. In thetransmission and reception testing in reflect mode, the radar of the car590 may be provided with a digital signal processor for digital signalprocessing (DSP) to infer target parameters such as distance, relativevelocity, and angle. Determination of nonconformance and remediation ofthe nonconformance may be left to the automaker.

FIG. 6 illustrates a system for testing an installed automotivearrangement using the flow of FIG. 5 in a first use case, in accordancewith a representative embodiment.

Since automotive radar antennas are often hidden behind plastic bumpermaterial and the manufacturing tolerances of the plastic bumper partsare crude with respect to the wavelength (e.g., millimeter or microwave)of the radar, there may be some interaction with the bumper materialthat may alter the beam shape and position. However, it is importantthat the location of a detected object agrees with the actual physicalposition of the object.

In the embodiment of FIG. 6, a car radar is tested using antenna-diodepair array 100 to detect the radar RF stimulus. The radar is set toilluminate a single location rather than scanning. The actual locationof the RF energy may be offset from the expected location due tointeraction with the bumper material and rough manufacturing tolerances.The antenna-diode pair array 100 allows detection of the actual beamlocation and measurement of any undesired offsets. This essentiallytests the transmit operation and RF beam alignment.

FIG. 7 illustrates a system for testing an installed automotivearrangement using the flow of FIG. 5 in a second use case, in accordancewith a representative embodiment.

In the use case of FIG. 7, the ability for the antenna-diode pair array100 to act as a programmable reflecting target for the automotive radaris shown. Unlike the receiver mode described previously which only teststhe Radar DUT 499 transmitter, the approach in the embodiment of FIG. 7tests both the Radar DUT 499 transmitter and receiver. When the diodesin the antenna array are forward biased they effectively short out thoseantenna and create a large reflection at the antenna position that theDUT can image. Two reflecting areas may be programmed to be spaced apartand brought closer and closer together to allow measuring the systemresolution in X and Y dimensions. Having a programmable reflectorcapability allows full testing of the Radar DUT 499 for both transmitand reception.

FIG. 8 illustrates a general computer system, on which a method ofcontrolling the two-dimensional array of antenna-diode pairs can beimplemented, in accordance with a representative embodiment.

The computer system 800 can include a set of instructions that can beexecuted to cause the computer system 800 to perform any one or more ofthe methods or computer-based functions disclosed herein. The computersystem 800 may operate as a standalone device or may be connected, forexample, using a network 801, to other computer systems or peripheraldevices. Any or all of the elements and characteristics of the computersystem 800 in FIG. 8 may be representative of elements andcharacteristics of the computer/controller 560 in FIG. 5 or othersimilar devices and systems that can include a controller and performthe processes described herein. The computer

In a networked deployment, the computer system 800 may operate in thecapacity of a client in a server-client user network environment. Thecomputer system 800 can also be fully or partially implemented as orincorporated into various devices, such as a central station, an imagingsystem, an imaging probe, a stationary computer, a mobile computer, apersonal computer (PC), or any other machine capable of executing a setof instructions (sequential or otherwise) that specify actions to betaken by that machine. The computer system 800 can be incorporated as orin a device that in turn is in an integrated system that includesadditional devices. In an embodiment, the computer system 800 can beimplemented using electronic devices that provide video or datacommunication. Further, while the computer system 800 is illustrated,the term “system” shall also be taken to include any collection ofsystems or sub-systems that individually or jointly execute a set, ormultiple sets, of instructions to perform one or more computerfunctions.

As illustrated in FIG. 8, the computer system 800 includes a processor810. A processor 810 for a computer system 800 is tangible andnon-transitory. As used herein, the term “non-transitory” is to beinterpreted not as an eternal characteristic of a state, but as acharacteristic of a state that will last for a period. The term“non-transitory” specifically disavows fleeting characteristics such ascharacteristics of a carrier wave or signal or other forms that existonly transitorily in any place at any time. Any processor describedherein is an article of manufacture and/or a machine component. Aprocessor for a computer system 800 is configured to execute softwareinstructions to perform functions as described in the variousembodiments herein. A processor for a computer system 800 may be ageneral-purpose processor or may be part of an application specificintegrated circuit (ASIC). A processor for a computer system 800 mayalso be a microprocessor, a microcomputer, a processor chip, acontroller, a microcontroller, a digital signal processor (DSP), a statemachine, or a programmable logic device. A processor for a computersystem 800 may also be a logical circuit, including a programmable gatearray (PGA) such as a field programmable gate array (FPGA), or anothertype of circuit that includes discrete gate and/or transistor logic. Aprocessor for a computer system 800 may be a central processing unit(CPU), a graphics processing unit (GPU), or both. Additionally, anyprocessor described herein may include multiple processors, parallelprocessors, or both. Multiple processors may be included in, or coupledto, a single device or multiple devices.

Moreover, the computer system 800 includes a main memory 820 and astatic memory 830 that can communicate with each other via a bus 808.Memories described herein are tangible storage mediums that can storedata and executable instructions and are non-transitory during the timeinstructions are stored therein. As used herein, the term“non-transitory” is to be interpreted not as an eternal characteristicof a state, but as a characteristic of a state that will last for aperiod. The term “non-transitory” specifically disavows fleetingcharacteristics such as characteristics of a carrier wave or signal orother forms that exist only transitorily in any place at any time. Amemory described herein is an article of manufacture and/or machinecomponent. Memories described herein are computer-readable mediums fromwhich data and executable instructions can be read by a computer.Memories as described herein may be random access memory (RAM), readonly memory (ROM), flash memory, electrically programmable read onlymemory (EPROM), electrically erasable programmable read-only memory(EEPROM), registers, a hard disk, a removable disk, tape, compact diskread only memory (CD-ROM), digital versatile disk (DVD), floppy disk,blu-ray disk, or any other form of storage medium known in the art.Memories may be volatile or non-volatile, secure and/or encrypted,unsecure and/or unencrypted.

As shown, the computer system 800 may further include a video displayunit 850, such as a liquid crystal display (LCD), an organic lightemitting diode (OLED), a flat panel display, a solid-state display, or acathode ray tube (CRT). Additionally, the computer system 800 mayinclude an input device 860, such as a keyboard/virtual keyboard ortouch-sensitive input screen or speech input with speech recognition,and a cursor control device 870, such as a mouse or touch-sensitiveinput screen or pad. The computer system 800 can also include a diskdrive unit 880, a signal generation device 890, such as a speaker orremote control, and a network interface device 840.

In an embodiment, as depicted in FIG. 8, the disk drive unit 880 mayinclude a computer-readable medium 882 in which one or more sets ofinstructions 884, e.g. software, can be embedded. Sets of instructions884 can be read from the computer-readable medium 882. Further, theinstructions 884, when executed by a processor, can be used to performone or more of the methods and processes as described herein. In anembodiment, the instructions 884 may reside completely, or at leastpartially, within the main memory 820, the static memory 830, and/orwithin the processor 810 during execution by the computer system 800.

In an alternative embodiment, dedicated hardware implementations, suchas application-specific integrated circuits (ASICs), programmable logicarrays and other hardware components, can be constructed to implementone or more of the methods described herein. One or more embodimentsdescribed herein may implement functions using two or more specificinterconnected hardware modules or devices with related control and datasignals that can be communicated between and through the modules.Accordingly, the present disclosure encompasses software, firmware, andhardware implementations. Nothing in the present application should beinterpreted as being implemented or implementable solely with softwareand not hardware such as a tangible non-transitory processor and/ormemory.

In accordance with various embodiments of the present disclosure, themethods described herein may be implemented using a hardware computersystem that executes software programs. Further, in an exemplary,non-limited embodiment, implementations can include distributedprocessing, component/object distributed processing, and parallelprocessing. Virtual computer system processing can be constructed toimplement one or more of the methods or functionality as describedherein, and a processor described herein may be used to support avirtual processing environment.

The present disclosure contemplates a computer-readable medium 882 thatincludes instructions 884 or receives and executes instructions 884responsive to a propagated signal; so that a device connected to anetwork 801 can communicate video or data over the network 801. Further,the instructions 884 may be transmitted or received over the network 801via the network interface device 840.

Accordingly, Millimeter-Wave Detect or Reflect Array enables selectivereflecting of an incident microwave signal or millimeter-wave signal, byproviding each antenna of the antenna-diode pair array 100 with an inputadapted to selectively receive a forward bias signal or a zero bias or areverse bias signal to apply to each of the diodes 120. This allowsselective control of the antenna-diode pair array 100 to operate as adetector that detects an incident microwave signal or millimeter wavesignal, or to operate as a reflector that reflects the incidentmicrowave signal or millimeter wave signal.

FIG. 9 illustrates an arrangement for determining angle of incidence ofa radar signal in accordance with a representative embodiment. Manyaspects and details of the various components of the system 900 arecommon to similar components discussed above in connection with variousrepresentative embodiments. These common aspects and details may not berepeated in order to avoid obscuring the presently describedrepresentative embodiment.

During operation, a vehicle 930 is equipped with a radar system (notshown in FIG. 9) having at least a portion of its components disposed inits front bumper 932. In the representative embodiment, a portion of theradar system including transmit and receive antennae and electronics areprovided at a curved portion 934 of the front bumper 932.

Radar signals are emitted from the radar system of the vehicle 930, andare incident on a array 940 of antenna-diode pairs 910, or rectennae,each including an antenna 912 and a diode 920. While various aspects ofthe testing of the radar in various embodiments are germane to thepresent description, the presently described representative embodimentusefully fosters testing of a radar system that transmits and receivesradar signals 936 from the curved portion 934 of the front bumper 932.

Determining the angle of arrival requires properly orienting the arrayof the car under test. A visible laser emitting (not shown)perpendicularly from the center of the panel of rectennas would allowrepeatable alignment. A laser emitting perpendicularly from the arrayonto a calibration fiducial on the car would ensure the panel is at theproper angle with respect to the car fiducial.

Another feature of the system of FIG. 9 is the optional inclusion ofLEDs to display the received microwave or millimeter wave fieldstrengths over the panel area. Specifically, as shown in FIG. 9 for oneof the antenna-diode pairs 910, the rectified DC output theantenna-diode pair 910 is provided to an analog multiplexer (MUX) 944.The output from the MUX 944 is provided an analog to digital converter(ADC) 948, where the DC value of the detected microwave or millimeterwave field, or the microwave or millimeter wave envelope is provided.The output from the ADC 948 is provided to an LED 950. As will beappreciated, an LED 950 can be associated with each antenna-diode(rectenna) 910 of the array 940. Moreover, the electronic componentsused to drive the LEDs 950 this can be located away from theantenna-diode pairs 910, for example at an edge of the antenna array forexample.

If the detected DC signal level from the ADC 948 is above apredetermined threshold value then a current is sent to the associatedLED 950, which then illuminates. The brightness of the output from theLED 950 is proportional to the received microwave or millimeter wavefield strength, and as such, the intensity of the ouput of the LED 950can be used as a measure of the incident field strength from the radarof the vehicle 930. Notably, the LED 950 may be a programmable colorLED, and the output from the LED 950 can be used to color-code orintensity-encode a programable color LED to produce live color-codedfield strength map. Among other benefits, the inclusion of LEDs 950provide the user a live view of the detected microwave or millimeterwave field strength over the area covered by the array 940.

FIG. 10A illustrates a simplified schematic diagram of a circuit 1000for determining an angle of incidence of a radar signal from a deviceunder test (DUT). Many aspects and details of the antenna array 1100 arecommon to those described above in connection with variousrepresentative embodiments. These aspects and details may not berepeated to avoid obscuring the presently described representativeembodiment.

In accordance with a representative embodiment, the circuit 1000 may bea component of the array 940 of antenna-diode pairs 910, or may be aseparate component for use with the system 900.

The circuit 1000 comprises a 180° hybrid 1020 that having two inputsports on top and two output ports, a summing port (0) 1022 and adifference port (180) 1024, on the bottom. Microwave or millimeter wavesignals from a pair of patch antennas (not shown in FIG. 10A) of thearray 940 of antenna-diode pairs 910 are routed through 180° hybrid1020, which subtracts the radar (microwave or millimeter wave) signalsfrom the vehicle 930. A difference of the radar signals of theneighboring pair of patch antennas is thus provided. As described below,this difference is provided to a rectifying diode 1026, and themicrowave or millimeter wave angle-of-arrival (see FIG. 10C) can bemeasured. This technique requires knowing the impinging microwave ormillimeter wave amplitude at both antenna 1010 and antenna 1012, andthus the field strength at both antennae 1010, 1012 connected to theinputs to the 180 degree hybrid 1020 must be known to allow extractionof the angle of arrival, which can be directly measured using rectennasneighboring antennae 1010 and 1012 (rectennas not shown).

As shown, the circuit 1000 also comprises a known microwave ormillimeter wave rectification circuit with low pass filtering prior tothe ADC. The series RC 1028 provides a path to ground but looks “open”to a low frequency signal; the choke 1030 blocks microwave or millimeterwave signals but passes the low frequency/DC signals.

Referring to FIG. 10A, and as discussed more fully below, A1 is therectified signal from a neighboring rectenna (not shown in FIG. 10A) tothe antenna 1010, and is proportional to the microwave or millimeterwave field strength at antenna 1010 feeding the hybrid 1020. A2 is therectified signal from another neighboring rectenna (not shown in FIG.10A) to the antenna 1012, and is proportional to the microwave ormillimeter wave field strength at the antenna 1012 feeding the hybrid1020. As described presently, knowing A1 and A2 is useful for theextraction of the angle of arrival of the incoming microwave ormillimeter wave beam.

With reference to FIGS. 10A and 10C, E1 is the microwave or millimeterwave field amplitude at wavelength λ provided to antenna 1010, E2 is themicrowave or millimeter wave field amplitude at wavelength λ provided toantenna 1012, and φ is the relative phase of these microwave ormillimeter wave signals the outputs A1, A2 and A3 are given by:

A1=E ₁ ²;

A2=E ₂ ²; and

A3=E ₁ ² +E ₂ ²−2E ₁ E ₂ cos(φ),

where φ₂=2πd sin(θ)/λ.

The measured diode outputs A1, A2 from respective neighboring rectennae,and output A3 from rectifying diode 1026 are used to solve for E1, E2,and cos(φ). Notably, φ is the relative phase between the microwave ormillimeter wave signals incident on the antenna 1010 and antenna 1012.Since cosine is an even function, equations A1-A3 are not discerned bysolid arrows from the dashed arrows FIG. 10B, because −θ produces thesame cos(φ) as θ. As will be appreciated from equations A1-A3, if A1-A3are known, cos(φ) is also known. From the trigonometric identity thatcos(φ)=cos(−φ) and the fact that φ=2πd sin(θ)/λ, equations A1-A3 do notdistinguish the incidence angle θ from −θ, because sin(−θ)=−sin(θ).However, knowledge of the radar's mounting position on the car plus thedetection “hot spot” pattern on the array provides sufficientinformation to decide which choice of angle (θ vs. −θ) agrees with themeasurements. Specifically, the angle of arrival circuit cannotdistinguished between microwave or millimeter wave coming in at θ vs −θ.But one angle (θ or −θ) can be eliminated by where the microwave ormillimeter wave is incident on the array 940. One arrival angle (eitherθ or −θ) will be consistent with the detected beam center from the arrayof detectors, and one will not.

FIG. 10B illustrates a simplified schematic diagram of a circuit fordetermining an angle of incidence of a radar signal from a device undertest (DUT). Many aspects and details of the representative embodimentdepicted in FIG. 10B are common to those described in connection withFIGS. 1-10A and FIG. 10C, and may not be repeated.

The circuit 1000 comprises a 180° hybrid 1020 having two inputs ports ontop and two output ports, a summing port (0) 1022 and a difference port(180) 1024, on the bottom. By routing microwave or millimeter wavesignals from a pair of patch antennas through a 180° hybrid, which addsthe radar (microwave or millimeter wave) signals from the vehicle 930,and detecting the sum output with a rectifying diode 1026, a microwaveor millimeter wave angle-of-arrival (see FIG. 10C) can be measured. Aswith the embodiment described in connection with FIG. 10A, thistechnique requires knowing the impinging microwave or millimeter waveamplitude at both antenna 1010 and antenna 1012, and thus the fieldstrength at both antennae 1010, 1012 connected to the inputs to the 180degree hybrid 1020, to determined of the angle of arrival.

Again, the circuit 1000 also comprises a known microwave or millimeterwave rectification circuit with low pass filtering prior to the ADC. Theseries RC 1028 provides an path to ground but looks “open” to a lowfrequency signal; the choke 1030 blocks microwave or millimeter wavesignals but passes the low frequency/DC signals.

Referring to FIG. 10B, and as discussed above, A1 is the rectifiedsignal from a neighboring rectenna (not shown in FIG. 10B) to theantenna 1010, and is proportional to the microwave or millimeter wavefield strength at antenna 1010 feeding the hybrid 1020. A2 is therectified signal a neighboring rectenna (not shown in FIG. 10B) to theantenna 1012 proportional to the microwave or millimeter wave fieldstrength at the antenna 1012 feeding the hybrid 1020. As describedpresently, knowing A1 and A2 allows extraction of the angle of arrivalof the incoming microwave or millimeter wave beam.

With reference to FIGS. 10B and 10C, E1 is the microwave or millimeterwave field amplitude at wavelength λ provided to antenna 1010, E2 is themicrowave or millimeter wave field amplitude at wavelength λ provided toantenna 1012, and φ is the relative phase of these microwave ormillimeter wave signals the outputs A1, A2 and A3 are given by:

A1=E ₁ ²;

A2=E ₂ ²; and

A3=E ₁ ² +E ₂ ²+2E ₁ E ₂ cos(φ),

where φ=2πd sin(θ)/λ.

The measured diode outputs A1, A2 from respective neighboring rectennae,and output A3 from rectifying diode 1026 allows us to solve for E1, E2,and cos(φ). Notably, φ is the relative phase between the microwave ormillimeter wave signals incident on the antenna 1010 and antenna 1012.Since cosine is an even function, equations A1-A3 are not discerned bysolid arrows from the dashed arrows FIG. 10B, because −θ produces thesame cos(φ) as θ. As will be appreciated from equations A1-A3, if A1-A3are known, cos(φ) is also known. From the trigonometric identity thatcos(φ)=cos(−φ) and the fact that φ=2πd sin(θ)/λ, equations A1-A3 do notdistinguish the incidence angle θ from −θ, because sin(−θ)=−sin(θ).Again, knowledge of the radar's mounting position on the car plus thedetection “hot spot” pattern on the array provides sufficientinformation to decide which choice of angle (θ vs. −θ) agrees with themeasurements. Specifically, the angle of arrival circuit cannotdistinguished between microwave or millimeter wave coming in at θ vs −θ.But one angle (θ or −θ) can be eliminated by where the microwave ormillimeter wave is incident on the array 940. One arrival angle (eitherθ or −θ) will be consistent with the detected beam center from the arrayof detectors, and one will not.

FIG. 11 illustrates an antenna array 1100 in accordance with anotherrepresentative embodiment. Many aspects and details of the antenna array1100 are common to those described above in connection with variousrepresentative embodiments. These aspects and details may not berepeated to avoid obscuring the presently described representativeembodiment.

The antenna array 1100 beneficially provides a possible lower costimplementation would be to use just a strip of rectennas and physicallyrotate the strip to cover a circular area. In operation, the firstlinear array 1101 rotates as shown.

The antenna array 1100 includes a first linear array 1101 ofantenna-diode pairs 1110, each including an antenna 1112 and a diode1120. The antenna array 1100 also includes a second linear array 1102 ofantenna-diode pair 1110, each including an antenna 1112 and a diode1120.

As will be appreciated, the same area as an array with multiple rows andcolumns can be measured with the square-root of the numbers ofantenna-diode pair 1110 (rectenna elements). As describe above, LEDs maybe used to display the measured fields. However, the display LEDs wouldneed to be modulated fast enough and in synchronicity with the rotationto create the correct visual image.

The polarization of the antennae 1112 is the direction of the microwaveor millimeter wave electric field vector. A pair of antennae one fromthe first linear array 1101 and one from the second linear array 1102 isneeded to accurately measure the field strength of an arbitrarilyaligned microwave or millimeter wave field. For example, should themicrowave or millimeter wave field be horizontally polarized, then firstlinear array 1101 and second linear array 1102 will match thispolarization at moments in time when they are rotated 90° from themoment depicted in FIG. 11. As such, and each antenna of the first andsecond linear arrays 1101, 1102 has a desired polarization at a 50% dutycycle. First and second linear arrays 1101, 1102 are adapted to rotatearound a common axis, and at a moment in time, the first linear array1101 (a first plurality of antennae) and the second linear array 1102 (asecond plurality of antennae) are co-polarized.

Although a millimeter-wave detect or reflect array has been describedwith reference to several exemplary embodiments, it is understood thatthe words that have been used are words of description and illustration,rather than words of limitation. Changes may be made within the purviewof the appended claims, as presently stated and as amended, withoutdeparting from the scope and spirit of millimeter-wave detect or reflectarray in its aspects. Although Millimeter-millimeter-wave detect orreflect array has been described with reference to particularcomponents, materials and embodiments, the millimeter-wave detect orreflect array is not intended to be limited to the particularsdisclosed; the millimeter-wave detect or reflect array of the presentteachings extends to all functionally equivalent components, structures,methods, and uses such as are within the scope of the appended claims.

The preceding description of the disclosed embodiments is provided toenable any person skilled in the art to practice the concepts describedin the present disclosure. As such, the above disclosed subject matteris to be considered illustrative, and not restrictive, and the appendedclaims are intended to cover all such modifications, enhancements, andother embodiments which fall within the true spirit and scope of thepresent disclosure. Thus, to the maximum extent allowed by law, thescope of the present disclosure is to be determined by the broadestpermissible interpretation of the following claims and theirequivalents, and shall not be restricted or limited by the foregoingdetailed description.

What is claimed:
 1. A device for detecting and selectively reflecting anincident microwave signal or millimeter-wave signal, the devicecomprising: a plurality of antennae disposed in an array; a diodedisposed at each input of each antenna, each diode having an inputadapted to selectively receive a reverse bias signal, or a zero biassignal, or a forward bias signal; and a switching device connected toeach input, and configured to selectively apply the forward bias signal,or the reverse bias signal or the zero bias signal to each of thediodes, wherein in forward bias, each of the plurality of antennaereflects the incident microwave signal or millimeter wave signal, and inzero bias or reverse bias each of the plurality of antennae detects theincident microwave signal or millimeter wave signal.
 2. The device ofclaim 1, further comprising: a 180° hybrid circuit disposed between apair of antennae, wherein an output of the 180° hybrid circuit isindicative of an angle of arrival of the incident microwave signal ormillimeter wave signal.
 3. The device of claim 2, wherein one output ofthe 180° hybrid circuit is provided to a rectifying diode to provide aDC output proportional to a difference between outputs of two of theplurality of antennae.
 4. The device of claim 2, wherein one output ofthe 180° hybrid circuit is provided to a rectifying diode to provide aDC output proportional to a sum of inputs of outputs of two of theplurality of antennae.
 5. The device of claim 1, wherein the diodedisposed at each input of each antenna is a zero bias Schottky diode. 6.The device of claim 1, wherein the array comprises a series of rows anda series of columns.
 7. The device of claim 6, wherein the plurality ofantennae in each of the series of rows are addressable by the switchingdevice as addressed rows.
 8. The device of claim 6, wherein in forwardbias addressed rows reflect the incident microwave signal or millimeterwave signal.
 9. The device of claim 6, wherein in zero bias addressedrows detect the incident microwave signal or millimeter wave signal. 10.The device of claim 5, wherein the plurality of antennae in each of aseries of columns are adapted to be addressed by the switching device asaddressed columns.
 11. The device of claim 10, wherein in forward biasthe addressed columns reflect the incident microwave signal ormillimeter wave signal.
 12. The device of claim 10, wherein in zero biasthe addressed columns detect the incident microwave signal or millimeterwave signal.
 13. The device of claim 1, further comprising: a delay lineadapted to receive the incident microwave signal or millimeter wavesignal to emulate a distance.
 14. The device of claim 1, wherein each ofthe plurality of antennae are spaced from one another by a distance thatis approximately λ/4, where λ is a wavelength of the incident microwavesignal or millimeter wave signal.
 15. The device of claim 1, whereineach of the plurality of antennae are spaced from one another by adistance that is approximately λ/2 and a device under test (DUT)transmits a single beam.
 16. The device according to claim 1, whereineach input is disposed at a center-tap of each of the antennae.
 17. Thedevice according to claim 16, wherein only a direct current voltage ismeasured at the center-tap.
 18. The device according to claim 17,wherein a magnitude of the direct current voltage is proportional to themagnitude of the incident microwave signal or millimeter wave signal.19. The device according to claim 1, further comprising a plurality ofarrays of antennae, wherein each of the plurality of arrays of antennaeare substantially flat.
 20. The device according to claim 19, whereinthe plurality of arrays of antennae are disposed adjacent to one anotherto form a curved array.
 21. The device of claim 1, further comprising alight-emitting diode (LED) connected to an output of at least one of theplurality of antennae to indicate a received field strength of the atleast one of the plurality of antennae.
 22. A device for selectivelyreflecting an incident microwave signal or millimeter-wave signal, thedevice comprising: a first plurality of antennae disposed in an firstlinear array, each antenna of the first linear array having an inputadapted to selectively receive a forward bias signal, or a zero biassignal or a reverse bias signal; a second plurality of antennae disposedin a second linear array, each antenna of the second linear array havingan input adapted to selectively receive a forward bias signal, or a zerobias signal or a reverse bias signal, wherein the first linear array andthe second linear array are disposed orthonormally to one another; adiode disposed at each input of each antenna; and a switching deviceconnected to each input, and configured to selectively apply a forwardbias or zero bias to each of the diodes, wherein in forward bias, eachof the first and second pluralities of antennae reflects the incidentmicrowave signal or millimeter wave signal, and in zero bias or reversebias each of the first and second pluralities of antennae detects theincident microwave signal or millimeter wave signal.
 23. The device ofclaim 22, wherein the first linear array and the second linear array areadapted to rotate about a common axis, and each antenna of the first andsecond linear arrays has a desired polarization at a 50% duty cycle. 24.The device of claim 22, wherein the first and second linear arrays areadapted to rotate around a common axis, and at a moment in time, thefirst plurality of antennae and the second plurality of antennae areco-polarized.